Currently, an image authentication system, which examines and authenticates alteration or non-alteration of image data by using Message Authentication Code (MAC) data or digital signature data corresponding to image data in an image file, is proposed. The conventional image authentication system is disclosed in, e.g., U.S. Pat. No. 5,499,294. Note herein that MAC data is obtained by processing a hash value of image data by key data that corresponds to a secret key of a symmetric key cryptography. Digital signature data is obtained by processing a hash value of image data by key data that corresponds to a private key of a public key cryptography.
However, the conventional image authentication system does not provide a user interface that is convenient and easy to use.